Redox Reactions and Electrochemistry — JEE Main PYQs

The pH and conductance of a weak acid (HX) was found to be 5 and $4\times 10^{-5}\mathrm{S}$, respectively. The conductance was measured under standard condition using a cell where the electrode plates having a surface area of $1{\mathrm{cm}}^2$ were at a distance of 15 cm a …

Consider the following electrochemical cell at 298 K
$\mathrm{Pt}\left|{\mathrm{HSnO}}_2^{-}(\mathrm{aq})\right|\mathrm{Sn}(\mathrm{OH}{)}_6{}^{2-}(\mathrm{aq})\left|{\mathrm{Bi}}_2{\mathrm{O}}_3(\mathrm{s})\right|\mathrm{Bi}(\mathrm{s})$.
If the reaction quotient at a giv …

Aqueous HCl reacts with ${\mathrm{MnO}}_2(\mathrm{s})$ to form ${\mathrm{MnCl}}_2(\mathrm{aq})$, ${\mathrm{Cl}}_2(\mathrm{g})$ and ${\mathrm{H}}_2\mathrm{O}(l)$. What is the weight (in g) of ${\mathrm{Cl}}_2$ liberated when 8.7 g of ${\mathrm{MnO}}_2(\mathrm{s})$ is reacted w …

For a closed circuit Daniell cell, which of the following plots is the accurate one at a given temperature?

MX is a sparingly soluble salt that follows the given solubility equilibrium at 298 K
$\mathrm{MX}(\mathrm{s})\rightleftharpoons {\mathrm{M}}^{+}(\mathrm{aq})+{\mathrm{X}}^{-}(\mathrm{aq})$; ${\mathrm{K}}_{\mathrm{sp}}=10^{-10}$
If the standard reduction potential for …

Consider the following reduction processes:
${\mathrm{Al}}^{3+}+3{\mathrm{e}}^{-}\to \mathrm{Al}(\mathrm{s}),{\mathrm{E}}^{\circ }=-1.66\mathrm{V}$
${\mathrm{Fe}}^{3+}+{\mathrm{e}}^{-}\to {\mathrm{Fe}}^{2+},{\mathrm{E}}^{\circ }=+0.77\mathrm{V}$ …

Consider the following electrochemical cell:
$\mathrm{Pt}|{\mathrm{O}}_2(\mathrm{g})(1\mathrm{bar})|\mathrm{HCl}(\mathrm{aq})||{\mathrm{M}}^{2+}(\mathrm{aq},1.0\mathrm{M})|\mathrm{M}(\mathrm{s})$
The pH above which, oxygen gas would start to evolve at anode is _____ (nearest inte …

In the given electrochemical cell, $\mathrm{Ag}(\mathrm{s})|\mathrm{AgCl}(\mathrm{s})|{\mathrm{FeCl}}_2(\mathrm{aq}),{\mathrm{FeCl}}_3(\mathrm{aq})\mid \mathrm{Pt}(\mathrm{s})$ at 298 K , the cell potential ( ${\mathrm{E}}_{\text{cell}}$ ) will increase when : …

Consider the above electrochemical cell where a metal electrode (M) is undergoing redox reaction by forming ${\mathrm{M}}^{+}$ ($\mathrm{M}\to {\mathrm{M}}^{+}+\mathrm{e}$). The cation ${\mathrm{M}}^{+}$ is present in two different concentrations ${\mathrm{c}}_1$ and …

200 cc of $\mathrm{x}\times 10^{-3}\mathrm{M}$ potassium dichromate is required to oxidise 750 cc of 0.6 M

Mohr's salt solution in acidic medium.
Here $\mathrm{x}=$

Electricity is passed through an acidic solution of ${\mathrm{Cu}}^{2+}$ till all the ${\mathrm{cu}}^{2+}$ was exhausted, leading to the deposition of 300 mg of Cu metal. However, a current of 600 mA was continued to pass through the same solution for another 28 minutes by keeping th …

X and Y are the number of electrons involved, respectively during the oxidation of ${\mathrm{I}}^{-}$ to ${\mathrm{I}}_2$ and ${\mathrm{S}}^{2-}$ to S by acidified ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$. The value of $\mathrm{X}+\mathrm{Y}$ is ____.

One mole of ${\mathrm{Cl}}_2(\mathrm{g})$ was passed into 2 L of cold 2 M KOH solution. After the reaction, the concentrations of ${\mathrm{Cl}}^{-},{\mathrm{ClO}}^{-}$ and ${\mathrm{OH}}^{-}$ are respectively (assume volume remains constant)

Molar conductivity of a weak acid HQ of concentration 0.18 M was found to be $1/30$ of the molar conductivity of another weak acid HZ with concentration of 0.02 M. If ${\lambda }_{{\mathrm{Q}}^{-}}^0$ happened to be equal with ${\lambda }_{{\mathrm{Z}}^{-}}^0$, then the differenc …

500 mL of 1.2 M KI solution is mixed with 500 mL of $0.2\mathrm{M}$ $\mathrm{KMnO}{}_4$ solution in basic medium. The liberated iodine was titrated with standard $0.1\mathrm{M}$ $\mathrm{Na}{}_2\mathrm{S}{}_2\mathrm{O}{}_3$ solution in the presence of starch indicator till the blue color disappeared. The volume ( …

Consider the following redox reaction taking place in acidic medium
$\mathrm{BH}{}_4{}^{-}(\mathrm{aq})+\mathrm{ClO}{}_3{}^{-}(\mathrm{aq})\to \mathrm{H}{}_2\mathrm{BO}{}_3{}^{-}(\mathrm{aq})+\mathrm{Cl}{}^{-}(\mathrm{aq})$
If the Nernst equation for the above balanced reaction is
$E_{\text{cell}}=E_{\text{cell}}^{\mathrm{o}}-\frac{\mathrm{RT}}{\mathrm{nF}}\ln Q$,
Then the val …

For strong electrolyte ${\Lambda }_{\mathrm{m}}$ increases slowly with dilution and can be represented by the equation ${\Lambda }_{\mathrm{m}}={\Lambda }_{\mathrm{m}}^{\circ }-\mathrm{A}{c}^{1/2}$
Molar conductivity values of the solutions of strong electrolyte AB at $18^{\circ }\mathrm{C}$ …

A volume of x mL of $5\mathrm{M}{\mathrm{NaHCO}}_3$ solution was mixed with 10 mL of $2\mathrm{M}{\mathrm{H}}_2{\mathrm{CO}}_3$ solution to make an electrolytic buffer. If the same buffer was used in the following electrochemical cell to record a cell potential of 235.3 m …

An electrochemical cell is constructed using half cells in the direction of spontaneous change
$\mathrm{Fe}(\mathrm{OH}{)}_2(\mathrm{s})+2{\mathrm{e}}^{-}\to \mathrm{Fe}(\mathrm{s})+2\mathrm{OH}(\mathrm{aq}){\mathrm{E}}^0=-0.88\mathrm{V}$
and …

Consider the following two half-cell reactions along with the standard reduction potential given : …

An electrochemical cell consist of the following two redox couples,
${\mathrm{M}}^{\times +}(\mathrm{aq})/\mathrm{M}(\mathrm{s})$ $[{\mathrm{E}}_{\text{red}}^{\ominus }=+0.15\mathrm{V}]$ and
${\mathrm{Fe}}^{3+}(\mathrm{aq})/\mathrm{Fe}(\mathrm{s})$ …

One half cell in a voltaic cell is constructed by dipping silver rod in ${\mathrm{AgNO}}_3$ solution of unknown concentration, other half cell is Zn rod dipped in 1 molar solution of ${\mathrm{ZnSO}}_4$.
A voltage of 1.60 V is measured at 298 K for this cell. What is the conc …

At 298 K, the molar conductivity of x %(w/w) MX solution (aqueous) is 123.5 S cm² mol⁻¹. The conductance of same solution is 1.9 × 10⁻³ S. The value of x is ____ × 10⁻².
(Given : cell constant =1.3 cm⁻¹; molar mass of MX is 75 g mol⁻¹, density of aqueous solution of MX at 298 K i …

Consider the following data :

${\mathrm{BaSO}}_4$ is sparingly soluble in water. If the conductivity of the saturated ${\mathrm{BaSO}}_4$ solution is $\times \mathrm{S}{\mathrm{cm}}^{-1}$ then the solubility product of ${\mathrm{BaSO}}_4$ can be given as.
(Here …

For a general redox reaction

Anode ${\mathrm{Red}}_1\to {\mathrm{Ox}}_1{}^{{\mathrm{n}}_1^{+}}+{\mathrm{n}}_1{\mathrm{e}}^{-}$
Cathode ${\mathrm{Ox}}_2+{\mathrm{n}}_2{\mathrm{e}}^{-}\to {\mathrm{Red}}_2{}^{{\mathrm{n}}_2-}$
Which of the fo …

500 mL of 0.2 M MnO₄⁻ solution in basic medium when mixed with 500 mL of 1.5 M KI solution, oxidises iodide ions to liberate molecular iodine. This liberated iodine is then titrated with a standard x M thiosulphate solution in presence of starch till the end point. If 300 mL of t …

Given at $298\mathrm{K}$: ${\mathrm{E}}_{{\mathrm{Fe}}^{2+}/\mathrm{Fe}}^{\ominus }=\mathrm{X}$ Volt
${\mathrm{E}}_{{\mathrm{Fe}}^{3+}/\mathrm{Fe}}^{\ominus }=\mathrm{Y}$ Volt

The ${\mathrm{E}}_{{\mathrm{Fe}}^{3+}/{\mathrm{Fe}}^{2+}}^{\ominus }$ in Volt at 298 K is given by :

A solution of aluminium chloride is electrolysed for 30 minutes using a current of 2 A. The amount of the aluminium deposited at the cathode is ______.
[Given : molar mass of aluminium and chlorine are $27\mathrm{g}{\mathrm{mol}}^{-1}$ and $35.5\mathrm{g}{\mathrm{mol}}^{-1}$ …

Which of the following electrolyte can be sued to obtain ${\mathrm{H}}_2{\mathrm{S}}_2{\mathrm{O}}_8$ by the process of electrolysis?

Given below are two statements :

Statement (I) : Corrosion is an electrochemical phenomenon in which pure metal acts as an anode and impure metal as a cathode.

Statement (II) : The rate of corrosion is more in alkaline medium than in acidic medium.

In the light of the above st …

For the given cell
${\mathrm{Fe}}^{2+}(\mathrm{eq})+{\mathrm{Ag}}^{+}(\mathrm{aq})\to {\mathrm{Fe}}^{3+}(\mathrm{aq})+\mathrm{Ag}(\mathrm{s})$
The standard cell potential of the above reaction is
Given :
${\mathrm{Ag}}^{+}+{\mathrm{e}}^{-}\to \mathrm{Ag}$ …

Based on the data given below: …

${\mathrm{FeO}}_4^{2-}\stackrel{+2.0\mathrm{V}}{\to }{\mathrm{Fe}}^{3+}\stackrel{0.8\mathrm{V}}{\to }{\mathrm{Fe}}^{2+}\stackrel{-0.5\mathrm{V}}{\to }{\mathrm{Fe}}^0$

In the above diagram, the standard electrode potentials are given in volts (over the arrow).
The value of …

Given below is the plot of the molar conductivity vs $\sqrt{\text{concentration}}$ for KCl in aqueous solution.

If, for the higher concentration of KCl solution, the resistance of the conductivity cell is $100\Omega$, then the resistance of the same cell with the dilute sol …

Standard electrode potentials for a few half cells are mentioned below:
…

Electrolysis of 600 mL aqueous solution of NaCl for 5 min changes the pH of the solution to 12.

The current in Amperes used for the given electrolysis is ____. (Nearest integer).

The standard reduction potential values of some of the p-block ions are given below. Predict the one with the strongest oxidising capacity.

The molar conductivity of a weak electrolyte when plotted against the square root of its concentration, which of the following is expected to be observed?

For a $\mathrm{Mg}\left|{\mathrm{Mg}}^{2+}(\mathrm{aq})\Vert {\mathrm{Ag}}^{+}(\mathrm{aq})\right|\mathrm{Ag}$ the correct Nernst Equation is :

0.1 M solution of KI reacts with excess of ${\mathrm{H}}_2{\mathrm{SO}}_4$ and ${\mathrm{KIO}}_3$ solution. According to equation
$5{\mathrm{I}}^{-}+{\mathrm{IO}}_3^{-}+6{\mathrm{H}}^{+}\to 3{\mathrm{I}}_2+3{\mathrm{H}}_2\mathrm{O}$
Identify the correct statement …

${\mathrm{O}}_2$ gas will be evolved as a product of electrolysis of :
(A) an aqueous solution of ${\mathrm{AgNO}}_3$ using silver electrodes.
(B) an aqueous solution of ${\mathrm{AgNO}}_3$ using platinum electrodes.
(C) a dilute solution of …

Consider the following electrochemical cell at standard condition. …

$0.2\%(\mathrm{w}/\mathrm{v})$ solution of NaOH is measured to have resistivity $870.0\mathrm{m}\Omega \mathrm{m}$. The molar conductivity of the solution will be ____ $\times 10^2\mathrm{mS}{\mathrm{dm}}^2{\mathrm{mol}}^{-1}$. (Nearest integer)

Correct order of limiting molar conductivity for cations in water at 298 K is :

The molar conductance of an infinitely dilute solution of ammonium chloride was found to be $185{\mathrm{S}\mathrm{cm}}^2{\mathrm{mol}}^{-1}$ and the ionic conductance of hydroxyl and chloride ions are 170 and $70{\mathrm{S}\mathrm{cm}}^2{\mathrm{mol}}^{-1}$, respectively. If molar conductance of 0. …

On charging the lead storage battery, the oxidation state of lead changes from ${\mathrm{x}}_1$ to ${\mathrm{y}}_1$ at the anode and from $x_2$ to $y_2$ at the cathode. The values of ${\mathrm{x}}_1,{\mathrm{y}}_1,{\mathrm{x}}_2,{\mathrm{y}}_2$ are respectively:

Given below are two statements :

1 M aqueous solution of each of $\mathrm{Cu}{\left({\mathrm{NO}}_3\right)}_2$, ${\mathrm{AgNO}}_3,{\mathrm{Hg}}_2{\left({\mathrm{NO}}_3\right)}_2;\mathrm{Mg}{\left({\mathrm{NO}}_3\right)}_2$ are electrolysed using inert electrodes,

Given : …

Given below are two statements :

Statement I : Mohr's salt is composed of only three types of ions-ferrous, ammonium and sulphate.

Statement II : If the molar conductance at infinite dilution of ferrous, ammonium and sulphate ions are ${\mathrm{x}}_1,{\mathrm{x}}_2$ and …

1 Faraday electricity was passed through ${\mathrm{Cu}}^{2+}$ (1.5 $\mathrm{M},1\mathrm{L})/\mathrm{Cu}$ and 0.1 Faraday was passed through ${\mathrm{Ag}}^{+}(0.2\mathrm{M},1\mathrm{L})/\mathrm{Ag}$ electrolytic cells. After this the two cells were connected as shown below …

Consider the following half cell reaction
${\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}(\mathrm{aq})+6{\mathrm{e}}^{-}+14{\mathrm{H}}^{+}(\mathrm{aq})\to 2{\mathrm{Cr}}^{3+}(\mathrm{aq})+7{\mathrm{H}}_2\mathrm{O}(\mathrm{l})$
The reaction was conducted with the ratio of …